TITLE:
Damage Caused by Psyllids and Influence of Climatic Factors in Brazilian Accesses of Guava Trees Cultivated in Organic System
AUTHORS:
Juliana Altafin Galli, Marcos Doniseti Michelotto, Maria Beatriz Bernardes Soares, Antônio Lucio Melo Martins, Ivan Herman Fischer
KEYWORDS:
Triozoida sp., Psidium guajava, Varietal Resistance, Temperature, Precipitation, Relative Humidity
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.10,
May
7,
2014
ABSTRACT: The psyllid (Triozoida sp.) is the primary pest of
guava tree in the Central Northern region of S?o Paulo State, Brazil. The
variation of climatic factors may influence directly or indirectly the behavior
of agricultural pests. The present work had objectives to evaluate the damages
caused by psyllid in accesses of guava trees in order to identify materials
with potential resistance to pest and the possible correlations of the damage
with the meteorological factors, in an orchard of guava conducted in an organic
system. Eighty-five guava accesses were evaluated. Each one was analyzed at
random 10 leaves containing the symptom of the psyllid attack, through visual
range of notes. The averages of the notes were compared by Scott-Knott test at
5% probability. The 25 accesses with the highest average damage of psyllid had
the data submitted to correlation (Pearson), with the minimum and maximum
temperature (°C), precipitation (mm) and relative
humidity (%). Guava accesses used commercially were the most susceptible to the
attack of psyllid, compared to the selections, with an emphasis to access “L4P14”,
“L7P28” and “L8P32B”, which were the least attacked. The study of correlation
between psyllid damages and meteorological factors, must be used the medium
temperature, relative humidity and rainfall accumulated in the period of 14
days before the evaluations. There is a positive correlation between minimum
temperasture, precipitation and relative humidity with the damage of psyllids
in leaves of guava.